Standard Roof Pitch Angles

Pitches of less than 2 12 are considered flat roofs even though they may be very slightly angled.

Standard roof pitch angles.

So use the 12 inch level as a constant run and 18 inch ruler as a variable rise. This means if a roof rises 4 in the length of 12 your roof pitch would be 4 12 or 18 43 degrees. Locate its tangent or tan and follow the left row for you to read its corresponding degree. Display of roof pitches 1 12 through 18 12.

Low slope roofs are from 0 to 3 12 in pitch. Find all the needed factors in order to determine the pitch angle s degree. You can also calculate roof pitch even without using a roof slope calculator. The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7.

If asphalt shingles are to be installed on a low slope roof special steps are required to avoid short roof life and roof leaks. In the usa the range of standard pitches is anywhere between 4 12 and 9 12. Usually average roof pitch is determined using the same roof length method. The most commonly used roof pitches fall in a range between 4 12 and 9 12.

Pitches above 9 12 are very highly angled and are designated steep slope roofs. High pitched roofs often need extra fasteners and their pitch can be as high as 21 12. Thatch is one of the oldest roofing materials and needs a steep pitch to drain properly some types of stone roofs have a very restrictive roof pitch. So the pitch of a roof is determined by how many inches the slope rises for every 12 inches it runs horizontally.

On blue prints architects engineers usually display the pitch of a roof in the format shown on the image where number 4 represents a rise and number 12 represents a length. Roof pitch and corresponding angles. Use the following formula which also describes a right triangle. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.

The 12 inch run is considered standard in roof pitch or angle terminologies. Commonly it is 3 4 th of span as per gothic rafter must be equal to span. In the uk the typical house has a pitch between 40 50 although 45 should be avoided. They have a pitch ranging from 4 12 to 9 12.

Roof pitch varies depending on culture climate style and available materials. Greek says one must keep rafter length in range of 1 9 to 1 7 th of span but as per roman style the standard dimensions are kept about 1 3 to 2 9 th of span with an angle of 23 to 24 degree. If a roof increases in height by four inches for every foot of horizontal run it is considered to have a 4 in 12 pitch or just a 4 pitch talk in terms of pitches and you will always be understood in the roofing universe. Some sources consider low slope to include 3 12 pitch roofs.